Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!hayes!tnixon
From: tnixon@hayes.uucp
Newsgroups: comp.dcom.modems
Subject: Re: Any way to get rid of 'end of session gobbledy gook'?
Message-ID: <3943.28327d57@hayes.uucp>
Date: 16 May 91 12:38:47 GMT
References: <422@wybbs.mi.org> <1991May1.160650.7799@unlinfo.unl.edu> <3267@unocss.unomaha.edu> <3939.282a9a30@hayes.uucp> <1991May14.231556.42791@eagle.wesleyan.edu>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 28

In article <1991May14.231556.42791@eagle.wesleyan.edu>,
flinton@eagle.wesleyan.edu writes: 

> Some years ago when I was using only 300 baud (ugh!) my ears could tell me
> that the reason my sessions with AT&T Mail ended without the gobbledy-gook,
> while sessions with my university mainframe ended with it, was simply this:
> AT&T Mail sent a long BREAK signal, during which my modem disconnected
> noiselessly, while the university simply dropped carrier, leaving my modem
> trying to interpret meaningless blobs of line noise until it decided there
> really wasn't any carrier left to demodulate.  Not a cleardown sequence in
> the V.32 sense, but the same effect from my vantage point.
> 
> [Toby: same thing apply at 1200? at 2400? -- seems to, though my ears fail me.]

Long-break disconnect is not required by any standard, although in 
Hayes modems it can be enabled at any speed.  It only operates in 
non-error-control async mode (&Q0).  If your modem receives a long 
break (1.6 seconds or more), it goes on-hook.  If you drop DTR (&D2) 
or issue an ATH0 command, the modem sends 4 seconds of break before 
going on hook.  Many non-error-control V.32 modems use this 
mechanism to try to eliminate garbage on disconnect -- but I still 
think using error control is the best way to solve the problem!

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net